Comma swordtail

[emeraldking]

Comma swordtail (Xiphophorus signum).
Technically, this wild swordtail species can not breed with another member of the Xiphophorus genus. This makes it possible to keep them with another Xiphophorus breed without risking hybridization. This is also the only swordtail species that can not breed with other swordtail and platy species.
Sexing as a juvenile is hardly possible. For they tend to mature pretty late when they have reached the adult size. Also the females will show a gravid spot pretty late (also close to adulthood).

Why this swordtail is called "comma swordtail" seems obvious. They show a comma sign in their tail. You won't find these at an average lfs.

 

[Colin_T]

Why won't they breed with other swordtails and platies?

 

[GaryE]

I wish I had known that about their having that barrier to hybridization. I was offered some last year and didn't have a tank empty - they could have gone in with my Xiphophorus milleri. Next time, if there is one....

 

[emeraldking]

Why won't they breed with other swordtails and platies?

Their sexual organs are not compatible with the sexual organs of other members of the Xiphophorus genus.

I wish I had known that about their having that barrier to hybridization. I was offered some last year and didn't have a tank empty - they could have gone in with my Xiphophorus milleri. Next time, if there is one....

Well Gary,
This is also the only Xiphophorus species that isn't capable to hybridize with other members of the Xiphophorus genus. So, next time that they're offered to you, you can just combine them with your Catemaco platies.
I've got mine combined with nezzies (Xiphophorus nezahualcoyotl), These are also known as "mountain swordtails". I myself don't prefer to use that name. For there are more wild swordtail species that live up in the mountains. So, the name itself would be a bit confusing.

 

[GaryE]

I kind of like saying 'nezahualcoyotl"! That species is my favourite swordtail (I know, these things are subjective).

 

[emeraldking]

I kind of like saying 'nezahualcoyotl"! That species is my favourite swordtail (I know, these things are subjective).

A lot of people struggle pronouncing it... LOL!
I've got more wild swordtail species overhere. Just love them...!

 

[Back in the fold]

OH man ! Those are nice. I love Swordtails. Had no idea there were so many different species. Xiphophorus helleri is all I ever knew.

 

[emeraldking]

OH man ! Those are nice. I love Swordtails. Had no idea there were so many different species. Xiphophorus helleri is all I ever knew.

Oh, when it comes to wild swordtail species, there are so many of them. But the Xiphophorus hellerii is the most wide spread of them.
Also the name "green swordtail" is not just something one should associate with just the Xiphophorus hellerii. There are more wild swordtail species that are considered being green swordtails. And there are also non green swordtails in te wild.
A part of those wild swordtail species come from tropical zones and a part of them come from subtropical zones in the tropical countries they occur. Those that are subtropical come from sub zones within a tropical country. Most of those subtropical ones are coming from the mountain areas. This is why the label "tropical fish" for a swordtail, is often questionable... The same goes for more fish from the tropical zone of this globe.

To give you an impression of a number of wild swordtail species:

Xiphophorus 1 | emeraldking-aquatics

www.emeraldking-aquatics.com

 

[TwoTankAmin]

Here is the background on this fish from the Xiphophorus Genetic Stock Center https://gato-docs.its.txstate.edu/jcr:67cc455b-3c27-49de-b11b-4b0358a61949/signum.pdf

Introduction:
The original strain of X. signum was collected in the Rio Chajmaic, Alta Verapaz,
Guatemala, in 1963. The 'Ch' strain survived for more than 11 generations of inbreeding, but
usually exhibited severely aberrant sex ratios (the first seven matings at the New York
Aquarium produced 22 males and 205 females, Kallman and Atz, 1966) and was eventually
lost. The current X. signum stock was received from Dr. J. H. Schroder, Munich, on 9/28/93,
but was derived from individuals of uncertain history. These fish were probably obtained
from aquarist Manfred Meyer, and were probably unrelated to the earlier strain.
This strain is a member of the southern swordtail clade and was described as a
subspecies of X. helleri (Rosen and Kallman, 1969; Morizot and Siciliano, 1982). Rosen
(1969) elevated signum to specific status, with the most notable character being the presence
of a grave spot, a micromelanophore pattern in the caudal fins of males and females. X.
signum is not known to have ever successfully hybridized, i.e., produced offspring, with any
other Xiphophorus species (Kallman, pers. comm.).

Sexing:
X. signum fish are sexed at 4 to 6 months of age. It is important that sex ratios be
determined as early as possible, in case of an extreme bias in sex ratios, and additional
matings are needed to ensure adequate production of the next generation. Always retain at
least one tank of males and one tank of females from the previous generation until it is
positively established that males and females exist in the current generation.

 

[GaryE]

Someday, on a forum, maybe a conservation project will break out. People reading could do the (serious) legwork to find a threatened species, and then once they have it, begin exchanging fish to maintain genetic diversity....

The breeding skills are here, and a fishkeeper can dream of a project breaking out. It would be good to see our hobby move away from just consuming and start producing.

 

[emeraldking]

Someday, on a forum, maybe a conservation project will break out. People reading could do the (serious) legwork to find a threatened species, and then once they have it, begin exchanging fish to maintain genetic diversity....

Well, this is already being going on in our country. Our national society of livebearers knows members that do keep and breed threatened livebearer species. And a part of those captive bred ones will be released in waters where those livebearers are endemic. I'm one of them who participate this project.

 

[TwoTankAmin]

I have been breeder some of the rarer and most certainly endangered B&W Hypancistrus from the Big bend of the Rio Xingu. When I started with zebra plecos I was one of several go to sources for tank raised fish in the states. Today not only are hobbyists breeding these in their tanks but they are also being farm raised in Indonesia. Right now the species I have that is fairly rare are true L173.

It was the zebras which started it all and which then enabled ne to go on to another species. People who do this in the staes most certainly trade fish for genetic reasons.

The problem with some of these fish is that they only live in just one part of one river which has been dammed. They are more than likely to become extinct in the wild over the newxt decade or so if not sooner.